Essentially four Mortars mounted on a single weapons carriage, the Heavy Quad-Launcher boasts a high rate of fire that makes it an excellent suppression weapon and in a direct-fire role against enemy infantry.[2][3] One of its primary drawbacks however is the long reload time after all four barrels have been fired, requiring the loader to hand-crank the breech close in order to feed in a new round for each barrel. The launcher also lacks the range of heavier Imperial Guard artillery, limiting its viability in the counter-battery role.[2]

The original thudd guns were mounted on a special motorized tractor, which could be controlled by the gun crew with a radio control box.[1] However, later models used by the Imperial Guard, such as the Lucius Pattern, must be towed into place, either by a Trojan or Centaur vehicle.[2][3]